march 4 - 7, 2018 hilton phoenix / mesa hotel mesa, …...displacement measurement spring probe life...

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March 4 - 7, 2018

Hilton Phoenix / Mesa Hotel

Mesa, Arizona

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Socket SupplierBiTS 2018Session 5 Presentation 1

March 4-7, 2018Burn-in & Test Strategies Workshop www.bitsworkshop.org

Life Cycles of Sockets;Specification vs Reality and Setting

StandardsJiachun (Frank) ZhouSmiths Interconnect

BiTS WorkshopMarch 4 - 7, 2018

Conference Ready mm/dd/2014



Life Cycle Test Methodology• Equipment

– Custom fixture design• 32 pins for life Cycles test • 32 pins for FDR test

– Customize Force/Measurement unit• Flexible to control the current density

– Contact medium • Top plate silver - Life Testing & FDR• Bottom plate Cu/Gold plating - Life Testing• Bottom plate silver - FDR

2Spring Probe Life Testing

Cres Vs. Life Measurement

Force Vs. Cres Vs. Displacement Measurement



Key Parameters/Assumption• What defines End of Life in your method?

– 5% over 200mOhms – Average Spec– Average + 2Std Spec

• Variables captured– Room Temperature– Normal Test 30mA/Customer Request maximum 1A.




Example Data Internal vs. External• FDR data

4

Force Measurement/Per Pin Res Vs. Life

Spring Probe Life Testing

• Life cycle data



Supplier Standards• What are the major influences on socket life?

– If “socket life” refers to spring probe, many factors, such as contaminations, spring force & stress, tip and surface wears, etc. can affect the life.

• How should life cycle be defined across the industry?– Really affected by usage environment and package– Actually, the life of spring probes from different suppliers is almost no differences if using same

materials and plating specifications.


Semiconductor Device ManufacturerBiTS 2018Session 5 Presentation 2



StandardsRahima MohammedSenior Principal Engineer

Intel Corporation





Agenda• End of Life Requirements

– scenarios in Validation and Test

• Socket Evaluation Methodology• Factory feedback• Need Standards

Dummy text maximum 30 characters 2



End of Life Requirements

Life Cycles of Sockets; Specification vs Reality and Setting Standards3

Validation Disciplines Validation CoveragePower Thermal and Performance Validation

Validates thermal design power (TDP), thermal sensor accuracy, thermal throttling algorithm and power delivery

Analog and electrical Validation

Validates electrical performance and IO design

Functional validation Validates logical functionality of the device

Test CoverageBurn-in Accelerates latent defects to meet time

zero reliabilityClass Continuity tests, power measurements,

dynamic frequency/voltage, test of all logic, arrays, I/O testing and SKU calculations

Circuit MarginalityValidation (CMV)

Validates the safety margins of circuits

System Level Validation (SLT)

Uses a product specific tester interface unit based on the reference motherboardSLT insures shipping quality parts and for measuring outgoing Quality

Quality and Reliability Extended life test

Test Transforms design into competitive products.Test Remove the defects introduced by Si fabrication process Class and SLT utilizes robotic handlers Socket EOL > 500K cycles

Validation Find Logical BugsValidation uses validation boards or reference boardsSocket and thermal system uses quick release retention designs or simple loading mechanismsSocket EOL > 200 cycles

Socket Electrical, Mechanical, Thermal Performance, Lifecycle and Cost are critical vectors



Additional Socket Evaluation Methodology• Equipment

– Tester/Handler with actual devices – Socket and test fixture– Cres measurement equipment

• Process– Maintenance Cleaning intervals– Insertion/extraction tracking

• Other– Evaluation are done per technology– Then done for every families– Per device, only tested for

opens/shorts, mechanical fit check

4Life Cycles of Sockets; Specification vs Reality and Setting Standards



Socket Evaluation Methodology

5

1

23

4

Life Cycles of Sockets; Specification vs Reality and Setting Standards

• Electrical – Daisy Chained Test Boards are used to evaluate the

force/pin and contact resistance per pin and variations between sockets of same or alternate technology

– Insertion loss and return loss

• Mechanical– Force/pin, socket tip wear on the DUT side and PCB

side, marks on the package– Checking for contamination on the pins under the

microscope• The socket is then run for 1000 mechanical cycles in

the system level testing setup, then through actual system level testing.

– Passed the short test and passed the long test content except for a specific content for 1000 cycles. Cres tests were repeated using the daisy chained test boards.

– Similar exercise were done for 2000, 3000 and 5000 cycles. At 5000 cycles, failed short and long test content for SLT.

Clear disconnect between socket vendor data of 100K cycles vs > 3K and < 5K cycles



Factory Feedback

6

Contact Resistance between Pre and Post cleaning Impedance vs Frequency Measurements

Manual reject validation shows ~50% of the SLT rejected failures actually pass with the validation sockets Direct impact on Yield

Life Cycles of Sockets; Specification vs Reality and Setting Standards



Need Standards• What are the major influences on socket life?

– Temperature cycling, power cycling, current carrying capability, how long the current is applied for, force distribution, electrical performance specially high speed data rates, package size, pitch, number of pins, routing of the signal, power and ground pins.

• How should life cycle be defined across the industry?– What is critical?

• Socket Electrical, Mechanical, Thermal Performance, Lifecycle and Cost are critical vectors• Socket specs has to be defined for that socket rather than the technology itself. It’s all the other

interaction that actually determines the performance of the socket in the specific application – What is controversial?

• Disconnect between the socketing technology and the whole socket performance itself – What is unnecessary?

• One size fits all for the technology will not work

7Life Cycles of Sockets; Specification vs Reality and Setting Standards




StandardsYoinjun Shi Twinsolution





Life Cycle Test Methodology• Equipment

– Custom fixture design• 32 pins~96 pins for life test• 36pins ~ 2000pins for F/Res test

– Cam mechanism for life cycling– Customize Force/Measurement unit

• Flexible to control the current density– Contact medium

• Top plate silver-Life Testing• Top Plate BeCu/Gold plating-FDR• Bottom plate BeCu/Gold plating

2

F/Res Vs. Displacement Measurement


Res Vs. Life Measurement



Life Cycle Test Methodology-Continue

3

F/Res Vs. Displacement Measurement Unit


Customize Fixture

Top Contact Plate

Bottom Contact Plate

Compress force measurement unit (500gf)

Res(Force/Measurement Unit)



Key Parameters/Assumption• Why was this method chosen

– Contact method is more life the IC ATE testing, it’s a steadily contact, no movement after the handler compressed.

– Silver and gold plated plate provide a good contact for top plunger and bottom plunger tip, to minimize the impact of contact point impact.

– CAM design more precise compare with cylinder piston, comparable wear acceleration with handler.– CAM design is also easy to control the running speed of the life testing.

• What defines End of Life in your method?– 5% over 200mOhms – Average Spec– Average + 2Std Spec

• Variables captured– Room Temperature– Normal Test 30mA/Customer Request maximum 1A.




Example Data Internal vs. External• IDM Data-Example3 (Switch Voltage)


Test Type: ParametricLow L. 0mVHigh L. 152mV

Mean: 91mVMin: 84mVMax: 119mV

Samples:500



Supplier Standards• How should life cycle be defined across the industry?

– Res/Contact force– Top plate material normally is solder or matt tin, which is quite different

from device, and this play a big role of life span. – Current density and on time is also another important factor to impact the

life span of pin.– Sampling data of measurement is good enough to test the life span, we do

not have to measure the pin by each cycle.




BiTS Contactor Life Cycle Panel Session

BiTS Workshop March 4 - 7, 2018

James MigliaccioQorvo



QorvoFormed from the merger of TriQuint Semiconductor and RF Micro Devices January 2015

We test a broad portfolio of RF devices: from low volume custom products to high volume general market devices at package and die level

Correspondingly need a variety of contactor solutions to satisfy divergent families of products with different needs

2BiTS Contactor Life Cycle Panel Session



End of Useful Life Requirements• Yield (electrical) or # of cycles (planned mechanical)

• Poor performance (low yield), customized by product as each device is unique

• Contact Performance Maintence System (CPMS) used to set standard maintenance and replacement intervals based on similar products initially

• Factory adjusts intervals based on testing• Typically will run a contact to failure (fatigue) if possible

• Replace all pins at once• Do not mix new and old contacts in same socket




Socket Evaluation Methodology

• Life Tester– Socket designed around product – Uses handler plunge assembly to cycle

devices– Socket mounted on test fixture

• Process– Plunge actual devices, mimic test time– Periodic read points to inspect/measure

4

• Other– Use force gauge to determine displacement versus normal force to get

average normal force per pin

BiTS Contactor Life Cycle Panel Session



Purpose of Internal Data• Our data is to estimate the expected life of a

socket/contact as used in production setting• Use data to set cleaning and replacement intervals

(CPMS)• Use actual devices rather than surrogates to determine

wear rate of contacts and damage to pads• Observe changes in contact surface (plating), shape

(wear), and damage




IDM Standards• What are the major influences on socket life?

– Real world use contamination, temp, current

• How should life cycle be defined across the industry?– Change in contact resistance is basically a default standard

(20%?)– Measured at nominal current and max current along with defined

duty cycle and recommended/max stroke– Common surrogate device design – Need a significant sample to determine population





Standards – Contact ResistanceValts Treibergs

R&D Engineering ManagerXcerra





Xcerra Cycling for Cres CharacterizationOFF-LINE CYCLING

• Mainly used for spring probe qualification

• 256 pin socket (LARGE SAMPLE SIZE)• Hardstop to set probe overdrive• Gold / Gold cycling surfaces – checked

often for wear• Force – Resistance – Deflection

evaluated at prescribed cycle intervals: 0, 10k, 50k, 100k, 250k, 500k, 1M, +

– MAP – Cres and Force at contact nominal test height– FReD – Contact consistency over entire stroke –

window of consistency, hysteresis

DYNAMIC CYCLING• Used primarily for elastomer and

cantilever contact qualification• 28-56 contact points in socket

configuration• Hardstop to set probe overdrive• Gold / Gold cycling surfaces – checked

often for wear• Automated Cres data collection in

programmable tri-temp chamber• Off-line Force / Resistance / Deflection

test also done at 250k intervals

BiTS 2018 - Valts Treibergs - Xcerra



Xcerra Off-Line Cycling DataMAP test

shows statistical trends in

performance –probability

plots –statistical

trends in force and resistance

FReD plots display internal frictional/Cres effects over time –

hysteresis and potential mechanical and plating problems




Xcerra Dynamic Cycling DataDynamic cycle

plots show statistical

trends in Cresperformance over various conditions




Key Parameters & Assumption• Off-line Cycling

– Very defined procedure – automated data collection – relatively quick– Large sample size – can keep retains for post-mortem analysis (SEM/other)– Best for spring probe applications– END OF LIFE: any mechanical failures (breakage or sticking), Cres standard deviation exceeds 20% of

average Cres value

• Dynamic Cycling– Best for elastomer/cantilever contacts, because elastomer performance is very specific to environment.

Scrub amount influences lifetime/performance– END OF LIFE: any mechanical failures (breakage or sticking), Cres standard deviation exceeds 20% of

average Cres value

• Variables captured– Forcing current during Cres measurement, contact interface metallurgy conditions, temperature




Lab vs. Real Test-Floor Performance Data• Lab data is only useful to define a data-sheet baseline set of

performance parameters – The best case scenario – ignoring everything else

• Socket suppliers interact with hundreds of customers, DUT types, handlers/probers, and test conditions. This makes it impossible to test for every possible combination and scenario

• How does production yield data relate to contact resistance? It depends. The onion must be peeled back carefully to rule out environment, device or setup related problems




Supplier Standards• What is Critical: Define a standard force and Cres baseline

(at what current and under what conditions)• What I want to see:

– From Customers: What statistics and under what conditions shall we provide data? How do you want this data presented? A standard template would be quite nice!

– From Xcerra and other Socket Suppliers: Complete test reports that include equipment, test conditions, methods, results with complete statistics

DATA SHEETS ARE WORTHLESS(unless supported by test methods & statistics)





StandardsTexas Instruments

James Tong





TI Contactor StrategyPass/Fail Criteria: > Life of 1M insertions,1 pins for all pitch by package type

Contactor Live Cycles Panel Session – Texas Instruments 2

MechanicalForce? – Do we care if it performs the test Tip wear? – Do we care if it does not affects the yield (electrical and mechanical)Package witness marks – No physical damage to DUT pad or ball Alignment features - alignment of contact affecting potential VM rejects/electrical performance

Electrical Mis-contact reliability

DC (Open/Shorts) –oFirst Pass conti%oYield recovery from Conti test

Frist Pass yieldFunc-Para failures

oRF or speed related testOthers

Temperature performance



Supplier Socket Self-Evaluation Methodology• Equipment for METS Test

– Standard contactor vendor test equipment

• FReD tester, Contactor cycler, Power suppliers, offline measurement tools, Infrared camera, network analyzer and contactor checker or OQC tools

– Tester/Handler with actual devices


• Pin specification• Cost Pin and contactor• METS test• 1M Cres test at temp• Mechanical test: scrub

wear test, Cu expose test

Vendor Self Qualification

• Build prototype contactor/s for engineering evaluation

• Prove RF/Speed characteristic of solution

• Small sample run to reduce risk at production qualification phase

Prototype Checkout

• Multiple samples of contactor to prove lifetime (Cres) and other spec envelop Temperature, Current, Speed/RF test performance

• Maintenance learning

Production Qualification

Emulating test application as best as possible



Santa’s List• The “Not-Me-Too” Supplier

Product distinction– Cres stability

• Pin structure design, Plunger material and hardness, Spring material and characteristic

– Temperature, current, plating of plunger and barrel if applicable

Support distinction– Application support from supplier

• Hot switching, Residual electrical charge handling, Current load sharing and distribution

• Standardization– Current carrying capability using METS– Insertions life expectancy base on test application– Compress pin height– Common test guide line of specifying solution for high

speed broadband and/or RF test needs


march 4 - 7, 2018 hilton phoenix / mesa hotel mesa, …...displacement measurement spring probe life...

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